A casement or an awning window generally refers to a sash that is attached to its frame by one or more hinges. The hinges can be located on any side of the sash and the frame though generally not on the lower edge of the sash and frame. In general, a casement window rotates along a horizontal plane (the hinges of a casement window defining a vertical rotation axis), while an awning window rotates along a vertical plane (the hinges of an awning window defining a horizontal rotation axis). Most casement and awning windows which employ the use of a crank lever or cam handle operator open outwardly so as not to interfere with the operator of the window.
Conventionally, windows, such as casement or awning windows, are locked by manipulation of a lock actuator handle which causes corresponding motion in a catch. The actuator is affixed to a window frame so that the catch engages a keeper on a corresponding section of a movable window sash to securely hold the sash against the frame. Where only one keeper on the sash is engaged by a catch, the locking mechanism is referred to as a “single-point” locking mechanism.
Also known in the art are “multi-point” locking mechanisms. Multi-point sash lock systems for casement windows generally typically have a single operating control, usually a lever. The lever is typically linked to a tie-bar that has multiple engaging structures disposed at intervals along its length. Operation of the lever causes the tie-bar to translate or move. Keepers are attached to the window sash proximate the locations of each of the engaging structures so that as the tie-bar moves, the engaging structures are moved in and out of engagement with the keepers. The entire sash lock assembly is usually concealed in the frame construction of the window, with the exception of the lever, which projects from a slot on the interior side of the window.
What is still needed is a low profile window lock for casement and awning windows.